Wind deflector

The one on Rick and Brenda Davis' IM is really nice. I think it's that black wire mesh you see used on the 911s and Boxters.

I believe it's the same on Dale Bates' roadster.

I'm sure Henry has a source for the materials.

I will be giving him a call.  Having a roll bar should make it easier (I think).  I did find a place that makes custom wind blocks-just waiting for them to respond to my email.

Ron

Ron O:

 

I built a plexi window into my roll bar quite a few years back.  Went to an auto glass place and got about 6 feet of universal side window channel (that which the side window slides up and down in) and bent it to fit the shape of the roll bar inside radii.  Slipped the pre-cut plexiglass up into it and then added a plastic stop, screwed into the roll bar on each side, just below the glass to hold it in place.  THEN, got really fancy by adding some glue-on velcro to the bottom of the glass (I think I used some channel stuff on the bottom, too  - I'll have to go look) and a corresponding velcro strip glued to my 1/4 tonneau. Push the two together and no air gets through to ruffle your hair.

 

gn

Here you go, Ron, from the old "Speedstershop" site:

 

After several years of getting really heavy wind buffets in the back of the head while riding around in my Speedster, I decided to try adding a wind blocker as seen on Miata’s and BMWs.    At first, I thought it would be cool to copy that mesh screening that they all seem to use.   I wanted to simply support it inside of the roll bar, but to do that I would need to support it completely AND be able to stretch it taut….Not an easy task.

 

A much easier approach was to incorporate a clear (or even tinted, if you prefer) Plexiglas window inside of the roll bar.   The first step was to find a suitable channel to hold the Plexiglas.  I drove my Speedster over to a local auto glass repair shop where we found some of the “U” channel used to guide roll-up side windows up and down within the door.

 

http://i49.photobucket.com/alb...1ChannelMaterial.jpg

 

There are a lot of different sizes to this material, and most of it has a fabric covering over a woven metal form in the shape of a “U”.  The material can be easily bent to reasonable radii, and need not require any finishing of the cut ends.   The owner of the auto glass place was taken with my Speedster, and gave me an 8’ length of 1⁄4” gap “U” material for free (!!)   He then sold me a piece of 1⁄4” Plexiglas to my dimensions for about $15……not a bad deal.

 

Before cutting, I measured inside of the roll bar from a point about where the tonneau cover sits when installed, thinking that I could use some Velcro on the bottom of the rear window frame and on the top surface of the tonneau to hold it all together when done.   More on that later.    Once I had the length I needed for the channel, I cut a piece to length.   While you could cut the material to length with a pair of tin snips, I prefer to use a Dremel tool with a cut-off wheel to make a nice, neat cut without frayed edges.    The Dremel cut it like “buddah”.

 

The channel can then be easily bent to follow the inside curves of the roll bar.   Do this slowly and carefully and it won’t bend all out of shape.   If you rush it, you’ll cause the sides of the “U” to splay outward and they’ll quickly become a 1⁄2” wide “V” instead of the 1⁄4” “U” that you want.   If that happens, just squeeze them back together with your fingers – be careful, though, that you don’t over do it.

 

When you get it to very closely follow the inside curves of the bar, you can fasten it in place along the center line of the pipe by drilling pilot holes through the “U” and through the roll bar, then installing suitable screws.    My roll bar is 3/16” thick, so sheet metal screws would not work (the bar material is too thick) so I used flat-head, counter-sunk, #6-32 machine screws and tapped the hole in the bar.   That is much easier than it sounds.     I counter-sunk the holes in the channel by just kissing the hole inside the channel with a 7/32” drill (go easy – just make the material cratered to accept the screw head better).    Once the holes are drilled and tapped, the channel is assembled to the roll bar and gently massaged to closely follow the inside of the curves AND center along the bar.    My know-it-all neighbor asked why I didn’t use “Pop” rivets instead of all the rigamarole of drilling and tapping and such.  Hmmmmm…I didn’t offer him a beer, either.    When all done, it should look like this:

 

http://i49.photobucket.com/alb...6/2FittedChannel.jpg

 

In order to cut the 1⁄4” Plexiglas to fit correctly the first time, I first cut a 1⁄4” template out of some scrap paneling material by holding it up to the roll bar and then drawing around the inside of the channel with a pencil.    I then hand-traced another line 1⁄4” outside of the line just drawn and cut along that.    I had to massage it a couple of times to make it fit perfectly, but it was pretty close to begin with. 

   

http://i49.photobucket.com/alb...3TemplateMock-up.jpg

 

Using that as a template for the Plexiglas, I traced around it onto the ‘glass and then cut it out with a saber saw using a 24T blade and moderate speed (3 out of 6 on my Skill Saber Saw).   This will leave a reasonably smooth cut which need not be polished as it will be going inside of the channel and will not be seen.   Before removing the protective film from both sides, I fitted it to the channel to make sure it would fit correctly (massaging where necessary), then removed the film and assembled it to the channel frame.

 

Now, the bottom channel – the most thought-provoking of the project.    I didn’t want to have mounting tabs showing at the ends of the bottom channel, but I wanted to secure the glass in place, too.    What I decided to do was install four #6X1/4” sheet metal screws through the top channel, just installed, and through the Plexiglas to hold it in place.    I painted them black, and they become invisible when installed.   I installed the bottom channel, and then installed another four, black, sheet metal screws in the bottom channel and that completed the job (almost).

 

http://i49.photobucket.com/alb...FittedPlexiglass.jpg

 

The last thing to do was install 1⁄2” wide Velcro between the bottom channel and the tonneau cover.   You can use the self-adhesive Velcro to get it located by putting the two pieces together and sticking it onto the bottom channel, then gently pushing the tonneau from the underside upwards to stick it to the bottom channel Velcro piece.   You can then use a screw driver to gently “unzip” the two pieces of Velcro.   I’ve found that the Velcro adhesive isn’t adequate to hold up under normal wind buffets at speed, so I marked along one edge of the Velcro on the tonneau, removed the Velcro and re-glued it with Dap Butyl Rubber-based contact cement.   Then I removed the Velcro from the bottom channel and re-glued it with the same DAP contact cement (it’s pretty good stuff).   That combination has been holding for about 6 years, now.

 

http://i49.photobucket.com/alb...356/CompleteRear.jpg

 

This set-up blocks pretty much everything coming from the rear of the car.    You still get a little buffeting from the sides, but no where near what it used to be.    The cockpit noise has also been greatly reduced such that you can now talk with your rider without shouting and you can actually hear the radio (when the exhaust noise has subsided!!)    All in all, it was very much worth the two hours effort to fabricate and install it.

Gordon, great write-up.

I'm not crazy about drilling holes into my roll bar, so I'll have to come up with another way to hold the wind block in place. 

I was considering making the plexiglass wind block almost the same size as the roll bar, so that the plexiglass sat up against the roll bar, just behind the seats.

I figured I could hold it in place with zap straps (for now).

Did you drill any holes in your plexiglass?  Are holes needed?

Ron

IO drilled four small holes to accept screws that hold it up in the channel.  They were #6 or so, IIRC , and went through the channel, then the glass, then the other side of the channel.  They're at the bottom of the glass in the corners and are black, so they disappear when assembled.  Lots of people are surprised to see glass in there, since my roll bar is black and the channels are black so it blends in nicely.

 

Drilling holes in Plexiglas isn't a big deal, although I would strongly recommend doing them on a drill press with minimal pressure so as not to crack the glass or allow the drill bit to get a bite and pull itself through too quickly.

 

You could certainly make a piece of plexi slightly larger than the roll bar opening and hold it up with zip ties.  I also looked into getting one of those net-style jobbies from an Audi or Mercedes or something, but couldn't find one in a salvage yard.

Gordon.

For those of us without roll bars, what do you think about the idea of mounting it directly to the body behind the the rear seat?  That would put it about 12 inches from the back of the drivers head, or does it need to be right behind the drivers head to be effective?

I undid all but the 3 tonneau snaps on each side and the tonneau does not sag at all.  Then you would just have a nicely done thin long hole cut in the tonneau for it to slip through.

I think you may even be able to still put the top up with it in place.  Or you could easily design it so it could quickly be removed.

Do you think 1/4 inch would still be rigid enough or would you need to go a little larger?

If it needs to be closer to the drivers head, brackets for it to slide into could probably be mounted on the sides of the rear seat area, just below the top hinge mounts.

 

Troy:

 

I see no reason why that wouldn't work.  I took the easy way out, since I had the roll bar already and just used that.  A couple of brackets attached to the body should work just as well, although honestly, I've never tried that approach.  If you go with a solid surface, rather than a mesh, I would expect that the brackets might need to be pretty beefy to take whatever buffeting might occur.

 

gn

I saw a BMW with something like you want on it so I took a couple of pics.  The plexi has slots where clear plastic velcro straps go through to hold it to the roll bars.  Where the plexi rests up against the roll bars there are little clear rubber bumpers, the kind you can get for kitchen cabinet doors and drawers at any hardware store.  These bumpers would prevent the plexi from scratching or rubbing on the roll bars.  I'd also think that a polycarbonate may be a better choice than plexi.  Hopefully the pics will help...

Thanks; that's exactly what I have in mind.

Gee, Ron.

 

The wind doesn't bother my hair.

 

I do collect a few insects, though, but they are usually dead from the impact.

Hrundi...Lane recommends SEXWAX. I've never seen a bug on him.....

You can do away with the "WAX" part, David.

Freestanding .  This one uses mesh not plexi .  Pretty sure the TR6 one is plexi .

 

http://www.mossmotors.com/Shop...9685&SortOrder=1

The main reason I want a wind block is to see if it will stop the exhaust/gas smell from being pulled back into the cabin area.

A slightly calmer cabin area would be nice too.

 

Latest update:

I bought a sheet of lexan today and just finished installing the wind block.  I used zap straps to attach the lexan to the roll bar.  Not the prettiest way to mount the wind block, but it was easy to mount, and seems very solid.

I'll post some photos soon.

Ron

Just had a thought. It would depend on the kind of seats you have, my seats have adjustable headrests, so you could make a bracket that fit over the two rods that go into the seat backs, I may try making a bracket, and post some images.

I installed my lexan wind blocker yesterday and took the IM out for a short highway drive today to see if there was less wind buffeting.

There wasn't.

Seems the wind block (roll bar) is too far away from the back of the driver/passenger's head to block the wind turbulence. 

Luckily, it was an inexpensive experiment.

I think SHRSpeedster is on to something.

Ron

 

 

Sorry it didn't work out, Ron.

However, you could leave it on and put a salad bar on one side of it.

Just thinkin' - the economy and all...